cubicweb #4673491 [devtools] call turn_repo_off in tearDown [validation pending]

[devtools] call turn_repo_off in tearDown

lets it catch leaked sessions even when running a single test

prioritynormal
typebug
done in3.20.0
load1.000
load left0.000
closed by#ff7f86d8393d [devtools] call turn_repo_off in tearDown (closes #4673491)
patch[devtools] call turn_repo_off in tearDown (closes #4673491) [applied]